Peptide

B7-33

Also known as

B7-33 relaxin analog · H2 relaxin derivative

Community talk. May contain inaccuracies. Not medical advice. Not a protocol. Not for human or animal use.

What it is

Identity	An experimental peptide modeled on part of relaxin, discussed for scar tissue, persistent tightness and organ fibrosis.
Route	Checked accounts describe injections under the skin. They do not establish that injecting near a scar targets it or that an oral form works.

Notes

B7-33 is an experimental peptide modeled on part of the hormone relaxin. People discuss it for scar tissue, persistent muscle tightness and organ fibrosis. A few users describe easier exercise or gradual improvement, but their accounts do not establish that scars changed or that B7-33 caused the improvement.

A simplified relaxin-family peptide. B7-33 copies part of relaxin's B chain. It acts at RXFP1, a receptor linked to tissue remodeling and collagen breakdown in laboratory work. This explains the scar interest, without establishing human scar removal. Praveen et al. (2023): lipidated B7-33 serum stability (Official context · Accessed 2026-09-30)

SubQ reports concern injection under the skin. The checked exercise account used that route. It is discussed as whole-body exposure, not proof that injecting near a scar targets it. B7-33 is not an organ-specific bioregulator, and these reports do not establish an effective oral form. B7-33: exercise account and same-author follow-ups (Personal report · Accessed 2026-09-30) · Experimental B7-33 for acne scars: proposal and collagen disagreement (Community discussion · Accessed 2026-09-30)

Source context — Praveen et al. (2023): lipidated B7-33 serum stability: Primary laboratory context, not an official human-use label. Full XML retrieved successfully by Python; web tool failed on API and PMC landing page was CAPTCHA-blocked. Human serum outside the body is not dosed participants; cell/animal findings do not validate human scar removal. Chemically modified derivative remains separate.

Source context — B7-33: exercise account and same-author follow-ups: One anonymous contributor, not independent corroborating reports. Product, outcomes and written units unverified; no dose conversion or airway/growth mechanism inferred. Some nested replies are collapsed in opened view; exact dates corroborated by dated search response.

Source context — Experimental B7-33 for acne scars: proposal and collagen disagreement: Mechanistic extrapolation, not a completed B7-33 treatment log. Claims of safety, selective scarring reversal and minimum eight weeks are unvalidated. Report about little reversal after two months concerns other peptide/procedure combinations, not demonstrated B7-33 nonresponse. Nested replies not all open; no exact dates inferred from changing relative timestamps.

What people notice

Easier exercise	One person reports less breathlessness and better gym endurance while also using BPC-157 and TB-500.
Scars and tightness	People hope for softer scars and freer movement. The calf discussion is a plan, and the accounts do not establish that scars changed.

Notes

Easier exercise is one reported benefit. One Reddit contributor described less breathlessness and more gym endurance while also using BPC-157 and TB-500. Their claim that B7-33 cleared the airways is an interpretation, not a verified explanation. B7-33: exercise account and same-author follow-ups (Personal report · Accessed 2026-09-30)

Softer scars and better movement remain hopes. Acne-scar and calf discussions seek less tethering, tightness and movement restriction. The calf thread contains a plan, not a result. Older recovery talk also mentions joint noise and post-strain recovery without a linked B7-33 outcome. Experimental B7-33 for acne scars: proposal and collagen disagreement (Community discussion · Accessed 2026-09-30) · B7-33 peptide: prospective calf-scar discussion (Community discussion · Accessed 2026-09-30)

Source context — B7-33 peptide: prospective calf-scar discussion: Prospective interest with competing explanations for longstanding cramps. No completed B7-33 benefit, amount, onset, duration or cycle. No sourcing text reproduced.

Doses people talk about

Older 100–500 mcg SubQ talk	An experimental band with no clear frequency or linked dose log; it is not an established daily total.
Acne-scar proposal	One author proposes about 300 mcg daily within 200–800 mcg daily by SubQ injection. This is an idea, not a completed dose-response report.
Promotional 1–2 mg example	A service-promoting post lists 1–2 mg, 2–3 times weekly, without a matching personal outcome log.
Actual-use amounts unclear	The exercise user writes 0.500mcg, later 0.800mcg daily; the units cannot be assumed to mean 500/800 mcg. Another user gives twice-daily frequency without an amount.

Notes

Older discussion: about 100–500 mcg SubQ. This experimental band has no clear frequency or linked dose log. It cannot be treated as a daily total or an agreed community routine.

Acne-scar proposal: 200–800 mcg daily. A Reddit author proposed about 300 mcg per day within that band, by subcutaneous injection. This was an extrapolated scar-treatment idea, not a completed B7-33 dose-response account. Experimental B7-33 for acne scars: proposal and collagen disagreement (Community discussion · Accessed 2026-09-30)

Promotional example: 1–2 mg, 2–3 times weekly. PeptidePeter lists these amounts beside that weekly frequency. The post promotes a peptide/bodywork service and provides no corresponding personal outcome log; do not combine it with the microgram daily proposals. PeptidePeter promotional B7-33 discussion (Secondhand community claim · Accessed 2026-09-30)

Actual-use reports leave important amounts unclear. The exercise contributor wrote 0.500mcg once daily, then 0.800mcg after two weeks. The units are unresolved; these cannot silently become 500 and 800 mcg. A recent user reports twice-daily injections without a public amount or daily total. B7-33: exercise account and same-author follow-ups (Personal report · Accessed 2026-09-30) · B7-33 and ARA 290: September user exchange (Community discussion · Accessed 2026-09-30)

Source context — PeptidePeter promotional B7-33 discussion: Commercial service promotion, no personal B7-33 result or dose-finding evidence. Amount-frequency pairing does not give a daily total. Broad efficacy, hormonal and blood-pressure assurances are not accepted.

Source context — B7-33 and ARA 290: September user exchange: No public amount, measured fibrosis change or detailed outcome. Title pairs two compounds without a resolved full exposure history. Replies move to private messages; those are not inspected. Same handles recur in acne thread and are not counted as extra independent outcomes.

Half-life, onset & duration

Felt onset	One combined-use account describes body, heart-area and stomach sensations in the first few days, without an after-injection time. Another describes gradual change without a clear interval.
Felt duration	The accounts do not establish how many hours a single dose feels active or how long any benefit persists after stopping.
Half-life	Not established in people. About 6 minutes for native B7-33 and 60 minutes for a modified peptide were measured in serum outside the body.

Notes

First few days: sensations in one combined-use account. The exercise contributor described body, heart-area and stomach sensations. They did not give an after-injection onset time or establish that those feelings reflected tissue repair. B7-33: exercise account and same-author follow-ups (Personal report · Accessed 2026-09-30)

A recent user describes gradual change. After starting in September 2026, a contributor said it felt as though it was slowly helping. The public reply does not identify the change or a precise benefit-onset interval. B7-33 and ARA 290: September user exchange (Community discussion · Accessed 2026-09-30)

No usable single-dose effect window. The checked users do not report how many hours a sensation or benefit lasts after one administration. A two-hour workout in the exercise account describes the workout, not B7-33's duration. B7-33: exercise account and same-author follow-ups (Personal report · Accessed 2026-09-30) · B7-33 and ARA 290: September user exchange (Community discussion · Accessed 2026-09-30)

Persistence after stopping is also unclear. A course lasting weeks does not show that a benefit survives a break, or that existing scar tissue was permanently removed. B7-33: exercise account and same-author follow-ups (Personal report · Accessed 2026-09-30) · Experimental B7-33 for acne scars: proposal and collagen disagreement (Community discussion · Accessed 2026-09-30)

No established human half-life emerges from these reports. Short-lived-peptide lore is not a measurement in people. The once-daily and twice-daily accounts do not measure how quickly B7-33 leaves the body. Laboratory numbers are explained separately below. B7-33: exercise account and same-author follow-ups (Personal report · Accessed 2026-09-30) · B7-33 and ARA 290: September user exchange (Community discussion · Accessed 2026-09-30)

Six minutes and sixty minutes belong to a serum experiment. A 2023 human-serum experiment outside the body at 37°C measured degradation half-lives of about six minutes for native B7-33 and sixty for a fatty-acid/PEG12-modified version. Different molecules, laboratory measurements: neither establishes a human injection interval or felt duration. Praveen et al. (2023): lipidated B7-33 serum stability (Official context · Accessed 2026-09-30)

Cycles people discuss

Four-week account	One person reports four weeks, five days on and two off, while also using BPC/TB. This does not establish a representative cycle.
Proposed courses	At least eight weeks in the acne-scar proposal and four to six weeks in the promotional post have no completed outcome supporting those calendars.

Notes

One completed account: four weeks, five days on and two off. This is the exercise contributor's calendar with BPC/TB co-use. It does not establish a representative cycle, an effective break length or combination safety. B7-33: exercise account and same-author follow-ups (Personal report · Accessed 2026-09-30)

Eight weeks and four to six weeks are different proposals. The acne-scar author argues for at least eight weeks using skin-renewal reasoning; PeptidePeter promotes four to six weeks. Neither supplies a completed outcome supporting that calendar. Experimental B7-33 for acne scars: proposal and collagen disagreement (Community discussion · Accessed 2026-09-30) · PeptidePeter promotional B7-33 discussion (Secondhand community claim · Accessed 2026-09-30)

Stacks

BPC-157 + TB-500	Used alongside B7-33 in the exercise account, so that story cannot show which compound caused the improvement or establish combination safety.

Notes

Stack context: Organ-system multi-bioregulator combinations belong to the broader catalog culture, not an established B7-33 protocol. The checked B7-33 self-report used BPC/TB too, which prevents clean attribution and does not establish combination safety. [community]

Watch for

Desired collagen changes	Scar commenters question whether an anti-scarring effect might also interfere with wanted collagen remodeling after cosmetic treatment. Selective scar removal is unproven.
Injection and product risks	Allergy, unknown impurities, redness, itching, lumps and bruising remain concerns; long-term safety is uncertain. Severe allergy or chest pain needs medical care.
Pregnancy and interactions	Pregnancy safety and medication interactions are unresolved. A user guide's blood-pressure concern is theoretical, without a human interaction study.

Notes

Scar selectivity is disputed. Acne-scar commenters question whether an anti-scarring effect could also interfere with desired collagen remodeling after cosmetic treatment. The same discussion contains both confident selectivity claims and doubts; neither establishes selective removal of unwanted scars in people. Experimental B7-33 for acne scars: proposal and collagen disagreement (Community discussion · Accessed 2026-09-30)

Mild-sounding reports do not establish safety. Allergy, unknown impurities and injection-site redness, itching, lumps or bruising are concerns. Long-term safety is uncertain. Severe allergic symptoms, chest pain, neurological changes or uncontrolled blood pressure/glucose need medical care, not a forum explanation about clearing tissue.

Pregnancy and medication interactions remain uncertain. Relaxin-related biology does not establish pregnancy safety for B7-33. A user-created guide raises possible blood-pressure interactions, but supplies no human interaction study. The BPC/TB account cannot validate stack safety either. PepTutor B7-33 compound guide (Community guide · Accessed 2026-09-30) · B7-33: exercise account and same-author follow-ups (Personal report · Accessed 2026-09-30)

Source context — PepTutor B7-33 compound guide: Secondary guide with commercial-adjacent navigation, no linked first-person evidence for many synthesized claims. Its no-public-user-reports assertion is contradicted by opened Reddit accounts. Safety ranking and categorical interaction/pregnancy instructions are not clinical findings. Retained only as attributed theoretical concern and internal rejection evidence.

Full notes

What it is and why people look it up

A simplified relaxin-family peptide. B7-33 copies part of relaxin's B chain. It acts at RXFP1, a receptor linked to tissue remodeling and collagen breakdown in laboratory work. This explains the scar interest, without establishing human scar removal. Official context
Fibrosis means excess scar-like tissue. The community interest spans tethered acne scars, stiff calves and suspected organ scarring. These are different problems. A theory about softening one kind of tissue cannot establish that every cramp, old injury or heart problem has the same cause. Reddit / r/AcneScars AnabolicMinds Reddit / r/Biohacking
SubQ reports concern injection under the skin. The checked exercise account used that route. It is discussed as whole-body exposure, not proof that injecting near a scar targets it. B7-33 is not an organ-specific bioregulator, and these reports do not establish an effective oral form. Personal report Community Reddit / r/AcneScars

Benefits people seek or report

Easier exercise is one reported benefit. One Reddit contributor described less breathlessness and more gym endurance while also using BPC-157 and TB-500. Their claim that B7-33 cleared the airways is an interpretation, not a verified explanation. Personal report
Softer scars and better movement remain hopes. Acne-scar and calf discussions seek less tethering, tightness and movement restriction. The calf thread contains a plan, not a result. Older recovery talk also mentions joint noise and post-strain recovery without a linked B7-33 outcome. Reddit / r/AcneScars AnabolicMinds Community

Doses people discuss

Older discussion: about 100–500 mcg SubQ. This experimental band has no clear frequency or linked dose log. It cannot be treated as a daily total or an agreed community routine. Community
Acne-scar proposal: 200–800 mcg daily. A Reddit author proposed about 300 mcg per day within that band, by subcutaneous injection. This was an extrapolated scar-treatment idea, not a completed B7-33 dose-response account. Reddit / r/AcneScars
Promotional example: 1–2 mg, 2–3 times weekly. PeptidePeter lists these amounts beside that weekly frequency. The post promotes a peptide/bodywork service and provides no corresponding personal outcome log; do not combine it with the microgram daily proposals. Reddit / r/BodyworkBiohackers
Actual-use reports leave important amounts unclear. The exercise contributor wrote 0.500mcg once daily, then 0.800mcg after two weeks. The units are unresolved; these cannot silently become 500 and 800 mcg. A recent user reports twice-daily injections without a public amount or daily total. Personal report Reddit / r/Biohacking

Half-life discussed in the community

No established human half-life emerges from these reports. Short-lived-peptide lore is not a measurement in people. The once-daily and twice-daily accounts do not measure how quickly B7-33 leaves the body. Laboratory numbers are explained separately below. Community Personal report Reddit / r/Biohacking

When people notice something

First few days: sensations in one combined-use account. The exercise contributor described body, heart-area and stomach sensations. They did not give an after-injection onset time or establish that those feelings reflected tissue repair. Personal report
A recent user describes gradual change. After starting in September 2026, a contributor said it felt as though it was slowly helping. The public reply does not identify the change or a precise benefit-onset interval. Reddit / r/Biohacking

How long an effect lasts

No usable single-dose effect window. The checked users do not report how many hours a sensation or benefit lasts after one administration. A two-hour workout in the exercise account describes the workout, not B7-33's duration. Personal report Reddit / r/Biohacking
Persistence after stopping is also unclear. A course lasting weeks does not show that a benefit survives a break, or that existing scar tissue was permanently removed. Personal report Reddit / r/AcneScars

Courses and breaks people describe

One completed account: four weeks, five days on and two off. This is the exercise contributor's calendar with BPC/TB co-use. It does not establish a representative cycle, an effective break length or combination safety. Personal report
Eight weeks and four to six weeks are different proposals. The acne-scar author argues for at least eight weeks using skin-renewal reasoning; PeptidePeter promotes four to six weeks. Neither supplies a completed outcome supporting that calendar. Reddit / r/AcneScars Reddit / r/BodyworkBiohackers
Seasonal courses come from broader bioregulator lore. Older 10–20-day courses repeated a few times yearly are not a B7-33 finding. Older 2–4-week recovery checkpoints likewise do not establish when B7-33 starts working. Community Community

Good to know

Scar selectivity is disputed. Acne-scar commenters question whether an anti-scarring effect could also interfere with desired collagen remodeling after cosmetic treatment. The same discussion contains both confident selectivity claims and doubts; neither establishes selective removal of unwanted scars in people. Reddit / r/AcneScars
Mild-sounding reports do not establish safety. Allergy, unknown impurities and injection-site redness, itching, lumps or bruising are concerns. Long-term safety is uncertain. Severe allergic symptoms, chest pain, neurological changes or uncontrolled blood pressure/glucose need medical care, not a forum explanation about clearing tissue. Community
Pregnancy and medication interactions remain uncertain. Relaxin-related biology does not establish pregnancy safety for B7-33. A user-created guide raises possible blood-pressure interactions, but supplies no human interaction study. The BPC/TB account cannot validate stack safety either. Community guide Personal report Community

What the laboratory timing actually means

Six minutes and sixty minutes belong to a serum experiment. A 2023 human-serum experiment outside the body at 37°C measured degradation half-lives of about six minutes for native B7-33 and sixty for a fatty-acid/PEG12-modified version. Different molecules, laboratory measurements: neither establishes a human injection interval or felt duration. Official context

From community discussion

Improved exercise and stopping belong to one person's story. The favorable exercise contributor later stopped while pursuing a different explanation for an eye problem. That is not an eye injury attributed to B7-33. Personal report
Calf-cramp interest is not a recovery log. An AnabolicMinds runner hoped B7-33 might relieve longstanding calf restriction after limited rehabilitation benefit. Their respondent had not used it; the five posts contain no completed outcome. AnabolicMinds
Recent users are still trying to define what changed. A September exchange asks what the slow improvement feels like and what dose was used, without public answers. The same participants appear in the acne-scar discussion, so they are not additional independent successes. Reddit / r/Biohacking Reddit / r/AcneScars
Mechanism enthusiasm meets calls for observable results. A PeptidePathways commenter distinguishes relaxin research from B7-33 use and asks for changes that someone else could verify. In Longecity, an unanswered 2021 dose question reflects curiosity about organ healing, not an established regimen or treatment result. Reddit / r/PeptidePathways Longecity