STUDresearch · Peptide
FLGR-242
Also known as
FLGR242 · FLGR 242 · FGLR242 · FGLR-242 · recombinant follistatin · Follistatin FLGR242 · BioLongevity FLGR242 · SlimAssist · FS I-I · FSI-I · FS-I/I · albumin-bound follistatin · MicroFLGR · BLL follistatin
Community talk. May be wrong. Not medical advice. Not a protocol. Not for human or animal use.
Peptide
Niche talk
Systemic
SubQ claim / IM conflict
Growth factors / muscle
Systemic recombinant follistatin analog with an albumin-binding tail.
What people say
FLGR-242 is a seller-named modified follistatin construct described as activin-sparing and albumin-binding. The checked materials are vendor pages, a patent statement and self-reports—not a disclosed human clinical program.
Doses people talk about
These are preserved claims, not clinical dose finding; FLGR-242, older FST-344 charts and SlimAssist are not interchangeable products.
How it may feel
The inspected accounts do not establish a characteristic acute effect. One SlimAssist user claimed rapid muscle change one week after a blended product; longer seller-promoted accounts describe weeks of training outcomes with no verified product-only attribution.
Vendor working range2.5–5 mg SubQ every 1–2 weeks
Seller-promoted range without a disclosed clinical arm.
Vendor higher-frequency line5 mg SubQ weekly
Marketing context labeled advanced in the source profile; not a validated tier.
Vendor lower amount2.5 mg, with copy suggesting a later 5 mg amount
Seller progression language retained as a claim, not adopted as guidance.
SlimAssist blend2 mg FLGR plus B vitamins
Blended product report; not equivalent to a 5 mg standalone FLGR vial.
Half-life & effect duration
- Half-life in the body
- Advertised estimateAbout 19 days
- Felt duration people report
- Blend-use accountDramatic change within 1 week
- Seller-promoted accountChanges across 8 weeks
Cycles people discuss
Vendor material describes 12–16-week blocks and weekly or fortnightly administration. Those calendars are marketing and community context, not validated clinical cycles.
Timing
A patent page asserts albumin-like persistence and mentions a seven-day canine half-life, but supplies no disclosed FLGR-242 human PK table and no inspectable canine methods in the cited passage. The advertised 19-day human-like number remains unestablished.
Stacks
GLP-1 drugs, testosterone and growth-hormone-pathway agents dominate the claims and make muscle or weight outcomes difficult to attribute to FLGR-242.
Watch for
Identity: FLGR vs FS-344 vs SlimAssist blend.
Tap a line to jump into the full notes. Research only — may be wrong.
Timing context & sources
Half-life in the body
No human FLGR-242 pharmacokinetic measurement was found; the advertised roughly 19-day figure is an albumin-binding assertion, not a reviewed human PK table.
A 2025 patent page says an albumin-binding construct may approach albumin persistence and separately states seven-day canine follistatin-construct persistence, but the inspected passage does not disclose a clinical FLGR-242 study or the canine methods and data table.
The patent claims concern albumin-binding constructs and do not name a human FLGR-242 trial. Vendor identity, sequence equivalence, route and assay are not independently verified.
- US Patent 12,377,158 — Enhanced peptide constructs for albumin binding (opens in a new tab)Description states human albumin has about a 19-day half-life, asserts an albumin-bound construct may retain at least 90% of that persistence and mentions a seven-day canine half-life for a follistatin construct; claims shown concern albumin constructs and Klotho.Patent assertions are not a peer-reviewed PK study; the inspected text does not provide a human FLGR-242 table or disclosed canine methods sufficient to validate the seven-day statement.
- BioLongevity Labs — Follistatin product page (opens in a new tab)Product page describes a fragmented modified FST-344 construct, an albumin-binding sequence, claimed activin sparing, research-only status and a current 10 mg two-vial SKU.Vendor marketing and product specification, not independent identity testing, animal methods or human clinical evidence.
- Tarzan Optimized glossary — FLGR242 (opens in a new tab)Seller-linked glossary lists both subcutaneous and intramuscular administration while repeating long-duration and muscle-growth claims.Seller-adjacent secondary material with no route-comparison trial, product verification or independent PK data.
Felt duration people report
No characteristic felt-duration window is established for FLGR-242; inspected claims range from dramatic change within one week to seller-promoted changes across eight weeks.
The one-week account involved a SlimAssist blend containing FLGR plus B vitamins and no objective measurements. A seller-promoter's eight-week account had inconsistent training and diet and no baseline bloodwork.
Shop-adjacent reports, blended product, unverified identity, co-interventions and no controlled follow-up prevent causal or duration estimates.
- Peptide Critic — Klotho/FLGR242 albumin-bound new tech (opens in a new tab)Same-author posts describe a 2 mg SlimAssist injection one week earlier, perceived rapid muscle change, a move from a planned weekly to two-week interval and reliance on the 19-day albumin story; product includes B vitamins.Single unverified blended-product report with no measurements, strong expectation and seller-community context; albumin half-life was treated as if it directly measured the product.
- Jay Campbell — Recombinant follistatin: the future of true muscle growth (opens in a new tab)Seller-promoter N-of-1 narrative describes pumps, strength and perceived leanness across about eight weeks while acknowledging inconsistent training, diet and absent baseline bloodwork.Commercial conflict, uncontrolled self-report, no baseline testing and multiple behavior confounders; product identity and independent measurements are unavailable. A current independent direct re-fetch returned a site error, so indexed page content was used to verify this commercial N-of-1 narrative.
Other context in this card
- Regeneron — COURAGE Phase 2 26-week lean-mass results with semaglutide ± trevogrumab ± garetosmab (opens in a new tab)26-week DEXA: semaglutide lean mass -6.5%; + trevogrumab about -3.3% to -3.8%; triplet with garetosmab -2.0%; triplet had more fat loss and worse tolerability/discontinuation. Antibodies, not FLGR-242.Different modality from a shop recombinant follistatin construct. Used only as separately identified human-pathway context for the skip-activin marketing claim.
- Kimera Chems — MID-35 vs FLGR242 comparison (opens in a new tab)States FLGR242 engineering claims (activin-sparing, ~19-day half-life) are manufacturer-only, no independent PK, late-2025 research-market arrival; summarizes ACE-083 Phase 2 muscle-volume-without-function plus ADA rates.Competing-vendor comparison page. ACE-083 is a different construct. Useful for evidence-quality framing, not FLGR identity testing.
- The Iron Den — Follistatin 344 thread (opens in a new tab)Jan–2026 board mixes BLL’s modified long-acting product with gray FS-344, quotes Jay 10 lb/12 weeks and a 20-day 100 mcg quarterly chart, notes ~$100/vial scarcity, heart-growth fear vs skeletal-not-cardiac counter.Anonymous bodybuilding forum; identity of the acquaintance’s vial unverified; staff posts are secondhand Jay marketing.
- X — Degen Doc n=1 DEXA note (2026-09-11) (opens in a new tab)Added FLGR-242 in June on reta, CJC/IPA and TRT; next DEXA showed a bigger lean-mass jump than prior months; explicitly would not call it proven or bullshit; asked for DEXA/photos not scale.Single confounded self-report with co-interventions and no independent assay of the vial.
- X — Jay Campbell Jake recap and rebound reply (2026-09-11) (opens in a new tab)Seller-promoter thread: months-long Jake n=1, ‘keeps moving the needle,’ under-fueling lesson; public reply asked whether FLGR242 has to be taken forever and whether muscle is lost on stop.Commercial conflict; co-training/diet; rebound question is unanswered in the thread.
- Peptide Critic — Klotho/FLGR242 thread later pages (dose spread and cruise talk) (opens in a new tab)Same-community logger later described 1 mg/day stretches, 5 mg weekly, wife 1–2.5 mg/week, SlimAssist 2 mg, ‘cruise forever,’ vascularity, and AAS co-use; others called it fountain-of-youth vs bollocks.Shop-community, unverified products, heavy co-intervention, strong expectation. Distinct from the earlier SlimAssist one-week post already sourced.
- Josh Holyfield — FLGR-242 / Follistatin before you buy (opens in a new tab)Independent 2026-09-02 synthesis: skip-activin vs COURAGE dual-blockade, 40 kDa vs semaglutide-size albumin trick, Farber patent vs BLL SKU, 1.5 lb/week headline vs antibody-class 1–3 kg over months, cessation reverse lore.Secondary commentary; some dose-math and bioactivity-loss figures are the author’s synthesis, not a FLGR PK paper. Used for community-skeptic framing.
What people say
- Vendor hypertrophy pitch: Skeletal-muscle gain / recomp while staying lean — Jay’s “7–10 lb lean” line in the course copy. n=1, shop-adjacent. anecdote
- GLP muscle-spare: The 2026 job on X — pin this so the tirz/reta cut doesn’t eat the gym. No controlled combo trial. forum
- 19-day half-life hope: Fewer pins than daily FS-344. That’s the albumin-binder claim, not a published human PK paper everyone cites. forum
- Selective myostatin / skip-activin: The reason they say it isn’t old FS-344. Preclinical/vendor language. forum
- Hit-or-miss logs: r/PEDs “experiences” threads are thin and split between “nothing” and protocol-copying. anecdote
- 2026-09 affiliate DEXA talk: BLL-affiliate posts claimed ~5 lb lean in 8 weeks after a TRT plateau; replies named TRT + reta as confounders in the same breath. anecdote
- 2026-09 n=1 who refused to oversell: One poster said they added FLGR in June on reta + CJC/IPA + TRT and the next DEXA lean jump looked bigger than prior months — and would not call it proven. anecdote
- Shop-adjacent IFBB contest-prep story: Jay’s Sep 2026 blogs keep repeating an Alex Padron “15 lb lean / 12%→4% in 10 weeks, only variable” line. Commercial conflict, not a trial. forum
- Peptide Critic diary (shop-community): One long logger described vascularity, workout craving, then a “cruise forever” weekly pin after an aggressive daily-mg stretch — with oral/oil AAS in the same window. anecdote
- Not gene therapy. AAV FS-344 clinic data is a different product class. trial
Doses people talk about
- Jay / BLL working talk: 2.5–5 mg SubQ every 1–2 weeks. forum
- “Advanced” vendor line: 5 mg SubQ weekly. forum
- Start-low copy: 2.5 mg first look, then maybe 5 mg. forum
- Not 100 mcg daily FS-344. Some reseller pages still paste the old FS chart onto FLGR — that’s the identity bug. forum
- SlimAssist is a blend (FLGR 2 mg + B-vitamins on the BLL page) — not the same as a 5 mg FLGR vial. forum
- 2026-09 public start-low log: 2.5 mg SubQ weekly with a planned bump after 4 weeks and a baseline DEXA the next morning. Still vendor milligrams. forum
- Peptide Critic spread: Same thread has 2.5–5 mg weekly, 1 mg/day then cruise, wife 1–2.5 mg/week, and SlimAssist 2 mg/week. Wild, shop-community. forum
- SlimAssist women-first copy (still current): 2 mg FLGR + 500 mcg B-complex; vendor says one vial covers ~2 weeks for a woman and is “insufficient for a week” in a male dieter. Not the 5 mg flagship vial. forum
- Framing: Vendor milligrams, not a trial arm, not a protocol. forum
How it may feel
- Administration talk: Seller-adjacent pages and community posts center on subcutaneous use, while at least one seller-linked glossary also lists IM. No clinical route-comparison data were found for FLGR242. forum
- Week 1–2: Some claim fullness; some claim expensive water. anecdote
- Over a 12–16 week vendor block: The screenshot window. Stacks (test, GLP, training) steal the credit. forum
- After a missed fortnight pin: The 19-day story is why people don’t panic the way they do after missing daily FS. Unverified. forum
- Stop: No classic PCT lore. Muscle-keep talk is the usual myostatin-class hopium. forum
- 2026-09 rebound question is now loud: “Does this have to be taken forever? Muscles lost once you stop?” sits next to vendor “keeps moving the needle” posts. No FLGR washout study. forum
- “Run through walls” stack talk: Affiliate logs mixing FLGR with SS-31 credit energy/strength to the combo. Attribution soup. anecdote
Cycles people discuss
- Vendor block: 12–16 weeks on, ~8 weeks off in the Jay protocol pages. forum
- Fortnight pins for the “normal use” screenshot. forum
- With a GLP: Continuous FLGR while the incretin is the thing people titrate. forum
- Not an 8-week SARM blast and not a daily 100 mcg FS run. forum
- Forever-cruise vs vendor block: A Peptide Critic logger planned no-break weekly after a growth spurt; vendor pages still 12–16 weeks on / ~8 off. Both are talk. forum
- “Less than 6 months is wasted” showed up in that same shop-community thread — opposite of short gray FS-344 camps. forum
Timing
- Pitch: ~19 days from the albumin-binding construct. Shop number, not a widely cited human PK table. forum
- FS-344 lore is 1–2 hours circulating — the whole reason this analog exists in ads. forum
- Route claim is not consistent: Seller-adjacent pages and community posts emphasize SubQ, but a seller-linked glossary lists both SubQ and IM. No human route-comparison pharmacokinetics were found. forum
- Downstream: Myostatin-class is weeks of training, not a 90-minute pump. forum
- Still no named-species PK table for the SKU. Promoter posts now quote ~40 kDa, albumin Kd <20 nM, glycine-serine linker. Semaglutide’s albumin trick is ~4 kDa; size-transfer is the skeptic line. forum
- ACE-083 (different follistatin trap) Phase 2: injected-muscle volume rose; function endpoints failed; anti-drug antibodies were common. Used as “follistatin-class can grow size without function.” Not this vial. trial
More on what it is
- What it is: A shop name for a modified Follistatin-344. Pitch: fragment so it skips activin, plus a 29-AA albumin binder so it hangs around ~19 days instead of hours. Jay Campbell / BioLongevity Labs is the loud source. forum
- Why people talk about it: 2026 muscle-spare-on-a-GLP tweets, “1.5 lb of muscle a week” YouTube, and the identity fight vs cheap FS-344 vials. forum
- How it works (plain): Follistatin soaks up myostatin (GDF-8), the parking brake on muscle. This analog claims to skip activin (the off-target people blame for weird growth) and ride albumin for a long half-life. forum
- Vs Follistatin 344: FS-344 on the map is the daily-mcg gray peptide / AAV gene-therapy story. FLGR is a milligram, weekly-or-fortnight pin in vendor copy. Do not copy 50–100 mcg FS onto this. forum
- Skepticism is the other half of the talk: r/PEDs and a 2026 “no-go” video called the citations animal-only and the albumin patent someone else’s. forum
- 2026-09 identity mix is still live: Iron Den treated Jay’s BLL modified product as old “FS-344” and quoted a 20-day 100 mcg chart. That is the milligram-vs-microgram mix-up. forum
- FS-I/I / skip-activin pitch (vendor/promoter): 2026 write-ups name an FS-I/I-style construct (keep myostatin, dump activin) plus a ~40 kDa albumin binder. Independent dose-response tables for this SKU were not found. forum
- Vs Apitegromab: That’s a latent-myostatin antibody with SMA trials. This is a recombinant ligand trap with a shop SKU. trial
- Activin-sparing tradeoff is not FLGR data: Regeneron COURAGE Phase 2 (sema ± trevogrumab ± garetosmab) showed extra lean-mass preservation on a GLP when activin A was blocked too, with worse triplet tolerability. Skeptics use that as “skip-activin may cut the human effect.” Different molecules. trial
Stacks
- + Tirz / reta / sema: The muscle-spare-on-a-cut screenshot. forum
- + Test / GH peptides: Advanced BB logs — credit is soup. forum
- Solo first if someone actually wants to know whether the analog did anything. forum
- Vs FS-344, not stacked with FS-344. Two follistatins is identity noise. forum
- + SS-31 in 2026-09 affiliate logs (“run through walls”). forum
- + Vesugen / HGH in a weekly Bod-Pod self-experiment post. forum
- Food/training as the screenshot gate: Jay’s Sep 11 Jake recap and Critic replies both say under-fueling kills the before/after. forum
Storage notes
- Lyophilized recombinant. Cool, dry. forum
- FLGR-242 vs FST-344 vs “recombinant follistatin” on the label is the first fight. forum
- SlimAssist ≠ 5 mg FLGR. Check the vial, not the blog title. forum
Watch for
- Not Follistatin 344 mcg charts. Wrong milligrams, wrong schedule. forum
- Animal-only citation pile is the main skeptic line. forum
- Shop-adjacent n=1s. anecdote
- Myostatin-class off-target lore (activin / GDF-11 / vascular) is why they claim the fragment exists — still a claim. forum
- Kidney-risk talk in some Jay clips at higher pins — not a mapped AE table. forum
- Identity: FLGR vs FS-344 vs SlimAssist blend. forum
- 2026-09 “1.5 lb muscle a week” vs antibody-ceiling talk: Independent write-ups contrast that headline with myostatin-antibody data more like 1–3 kg extra lean over months on TRT. Neither is an FLGR RCT. forum
- Price / exclusive SKU: Peptide Critic shoppers say BLL / Paramount / Alpha; sale-timing to get under ~$200/vial. forum
- Farber albumin-binder patent vs BLL SKU is a recurring skeptic point (public licensing not shown). forum
- WADA myostatin-class ban still covers follistatin-binding proteins for tested athletes. trial
- Immunogenicity question for a recombinant with a non-native albumin-binder — raised because ACE-083 had ADA rates. No FLGR ADA dataset. trial
Evidence mix
Mostly community / anecdote tags
Full: every bullet (trial + community). Use Scan for a faster bro-science read.