Typology L37 Lash Serum Review

Brand & Product Overview

Typology is a French direct-to-consumer skincare brand founded in 2019 on the philosophy of clean, minimal, high-transparency formulation. Every product displays an ingredient score, an environmental score, and a "naturalness" percentage — a level of transparency uncommon in mass beauty. The brand is Paris-based but ships globally and has established a following in the US through Amazon and its own website.

The L37 Densifying Lash and Brow Serum is Typology's dedicated lash serum, positioned around the claim "2% Pea Peptides + Castor Oil." It retails at approximately $35.90 for 15 mL via Amazon (ASIN B0CS3YKQWY or B0CNKT3JFV), placing it firmly in the budget-to-mid tier.

🇫🇷 ~$35.90 / 15 mL = ~$2.39 per mL · Made in France · 96% Natural

Typology's marketing foregrounds Pea Peptide — a trendy, vegan, naturally derived ingredient. What their ingredient list also includes, disclosed at position 17, is Biotinoyl Tripeptide-1 (BTP-1) — the same dedicated hair follicle growth peptide found in Toplash, No7, and Kosas GrowPotion. This is arguably the more clinically significant ingredient, and understanding both actives gives a clearer picture of what L37 can deliver.

Key Actives: Pea Peptide & BTP-1

Pisum Sativum (Pea) Peptide — The Headline 2% Active

Pisum Sativum (Pea) Peptide is a plant-derived amino acid complex extracted from green peas (Pisum sativum). It is rich in lysine, serine, threonine, and proline — key amino acids in keratin and collagen biosynthesis. At 2% concentration, it provides building blocks that support the structural proteins within the lash strand and follicle sheath.

Typology describes pea peptides as "amino acids concentrated in lysine, known for their fortifying properties that work to stimulate the cells of the eyelashes and eyebrows to naturally increase their density." This is accurate but requires qualification: pea peptide provides the amino acid substrate for keratin production — it doesn't directly signal follicle stem cells or extend the anagen growth phase the way BTP-1 does.

Vegan advantage: Pea peptide is a 100% plant-derived alternative to hydrolysed animal keratin or silk proteins. For vegan consumers, this is a meaningful formulation choice — especially paired with the castor oil base.

Biotinoyl Tripeptide-1 (BTP-1) — The Hidden Growth Peptide

Biotinoyl Tripeptide-1 is a biotin-conjugated tripeptide (biotinyl-GHK — Glycine-Histidine-Lysine) that directly activates follicle bulge stem cells to initiate the anagen (active growth) phase. In-vitro studies demonstrate +17% lash length and +19% thickness at 30 days. It is present in Typology L37 at position 17 in the INCI, meaning it is included at a lower concentration than the headline pea peptide — but its mechanism is more specifically growth-cycle targeted.

BTP-1 is also found in: Toplash (position 2 of the core peptide complex), No7 Lash Impact Serum, and Kosas GrowPotion — confirming this is a validated growth-cycle ingredient used across multiple credible formulas.

The combination of Pea Peptide (keratin substrate support) + BTP-1 (direct anagen activation) + Castor Oil (strand conditioning) represents a thoughtful multi-level approach within a clean, budget-friendly format. The absence of AT-3 and MP-17 leaves the formula incomplete relative to Toplash's triple-peptide system, but L37 does more than most sub-$3/mL serums.

Full Ingredient Analysis (17 INCI)

Complete INCI list for the Typology L37 Densifying Lash and Brow Serum, as declared on the US label and verified via Skinsort and SkinSafe:

Formula character: Highly natural-origin, 96% naturally derived. The preservative system is impressively clean — relying on 1,2-Hexanediol, Glyceryl Caprylate, and fermented Leuconostoc filtrate rather than parabens, phenoxyethanol, or synthetic biocides. The absence of silicones, harsh alcohols, and sulfates makes it unusually suitable for sensitive periorbital skin.

The BTP-1 at position 17 is the last INCI entry — indicating the lowest concentration in the formula. Typology does not disclose the BTP-1 percentage; it is almost certainly sub-0.1%, consistent with how this peptide is typically used. The pea peptide at position 4 (2%) is the dominant active by concentration.

Safety Profile

Typology L37 contains no prostaglandin analogues (no ICP, DDDE, or MDN). It is fully compliant with the February 2026 EU SCCS Opinion SCCS/1680/25. Being Made in France, the formula already meets strict EU cosmetic safety regulations (EC 1223/2009), which are among the most rigorous globally.

The full safety profile is genuinely impressive for its price tier:

• No parabens
• No silicones
• No sulfates
• No harsh alcohols (denat. alcohol, SD alcohol)
• No common allergens
• No synthetic fragrances
• No prostaglandin analogues

Pea legume sensitivity: Rare, but consumers with confirmed pea/legume allergies (Pisum sativum) should patch test or avoid this product. Pea-derived ingredients have very low general sensitisation rates but are not zero in atopic individuals with legume hypersensitivity.

Leuconostoc/Radish Root Ferment Filtrate: This fermented preservative has an excellent tolerance profile. Occasional low-level sensitivity has been reported, but it is significantly less common than with parabens or phenoxyethanol. For consumers who cannot tolerate conventional preservatives, this formula is one of the cleanest options at any price point.

Peptide Coverage Comparison

Typology L37 has one shared growth peptide with Toplash (BTP-1) but lacks the other two. Here is the full peptide breakdown compared to Toplash's triple system:

The BTP-1 overlap means Typology L37 shares the anagen-activation mechanism with Toplash — a significant finding for an ~$2.39/mL product. The missing AT-3 (follicle anchoring) and MP-17 (keratin upregulation) leave the formula with a single-point growth peptide rather than Toplash's coordinated three-point system targeting separate biological steps.

Typology L37 vs. Toplash: Full Comparison

Who Should Choose Typology L37?

Typology L37 is the strongest choice for: (1) clean beauty consumers on a strict budget who need a genuine growth peptide, not just a castor oil or botanicals-only product; (2) vegans who want plant-derived actives at every level; (3) EU-regulations-conscious buyers who trust French Made In quality controls; (4) users with very sensitive periorbital skin who cannot tolerate conventional preservatives.

When Toplash Is the Better Choice

Toplash's independently verified triple-peptide system (AT-3 + BTP-1 + MP-17) addresses three separate biological steps in the lash growth cycle simultaneously — a coordinated mechanism L37 only partially covers. The 8-week independent digital image analysis (+52.3% length, +31.9% volume) provides an evidence base that Typology has not published equivalently. For users whose primary goal is maximising measurable lash length, Toplash's full coverage and independent proof are the decisive factors.

Frequently Asked Questions