A lab-made copy of human follistatin, applied to the scalp to lift the brakes on hair follicles. The idea is plausible and the early signal is intriguing, but no controlled human study shows the leave-on serum works, and large proteins struggle to pass through skin. Local irritation is the main realistic downside. (Full Review)

Protocol

Application

Once or twice daily

Leave-on, applied to a clean, dry scalp

Form

Multi-peptide scalp serum

No established standalone protocol for the isolated peptide

Duration

Ongoing, continuous use

Gains fade after stopping; no taper or cycling needed

Time to effect

Visible hair change

~4 months

At least about four months of consistent use, per manufacturers

Benefits

Low: Increased follicle density and hair-shaft thickness

Speculative: Anagen phase extension and reactivation of dormant follicles; synergy within multi-peptide growth-factor serums

Contraindications

Active scalp dermatitis

Broken or inflamed scalp skin

Scarring alopecia

Known allergy to any formulation component

Pregnancy or breastfeeding (precautionary)

Key Interactions

Concurrent prescription topicals on the same area (topical minoxidil, topical corticosteroids)

OTC scalp products containing exfoliants or alcohols

Oral supplements to boost follistatin or inhibit myostatin

Additive follicle-stimulating actives (minoxidil, copper tripeptide-1/GHK-Cu, caffeine, adenosine, procapil-type peptides)

Microneedling

Risk & Side Effects

Low: Local skin and scalp irritation

Speculative: Theoretical local growth-signal modulation; unknown long-term topical safety

Monitoring

Marker	Target	Why
Ferritin (iron stores)	50–100 ng/mL	Low iron stores drive diffuse hair shedding and blunt treatment response
TSH	0.5–2.5 mIU/L	Thyroid dysfunction is a common reversible cause of hair loss
Vitamin D, 25-OH	40–60 ng/mL	Low vitamin D is associated with hair-cycle disturbances and follicle health

Cadence: Standardized photographs at ~4 weeks, 4 months, then every 4–6 months; labs rechecked only if baseline abnormalities or shedding changes

Qualitative Assessment

Reduced daily shedding (hairs in brush, shower, or pillow)
Visible new short regrowth at the hairline or part
Increased perceived density or scalp coverage in consistent lighting
Improved hair-shaft thickness and manageability
Absence of scalp irritation, redness, or flaking as a tolerability marker

Sh-Polypeptide-86 for Hair Regrowth

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment