The hair growth product market is worth billions globally — and a significant portion of that money is spent on products that don’t work. Not because all hair growth science is fraudulent, but because effective ingredients exist alongside a lot of marketing-heavy, evidence-light products that capitalise on people’s anxiety about hair loss.
This guide is about telling the difference. It covers what the evidence actually supports, which products are worth investing in, and what to skip.
Why Hair Growth Products Are So Easy to Get Wrong
Hair loss is emotionally charged. It affects confidence, identity, and how people see themselves. This emotional weight makes consumers more susceptible to claims — and manufacturers know it.
Add to this that hair change is genuinely slow (hair grows roughly 1cm per month, and growth cycle changes take three to six months to become visible), and you have the ideal conditions for selling products that “work” before people realise they don’t.
Most unsuccessful hair growth products fail for one of three reasons:
1. The active ingredient has no credible evidence. Biotin shampoos, collagen sprays, keratin treatments — plenty of marketing, minimal clinical data for hair regrowth.
2. The concentration is too low. An ingredient can be clinically proven at 5% concentration but present at 0.1% in a product. The label lists it; the dose doesn’t do anything.
3. The delivery method is wrong. Biotin in a rinse-off shampoo does essentially nothing. The active never reaches the follicle at a meaningful concentration.
Understanding these failure modes helps you evaluate any product.
Hair Growth Products That Have Actual Evidence
Minoxidil (Topical, 2–5%)
Minoxidil is the most clinically validated topical hair growth treatment available without a prescription. Originally developed as a blood pressure medication, it was discovered to stimulate hair growth as a side effect. It’s now the active ingredient in most leading hair loss treatments worldwide.
How it works: Widens blood vessels around follicles, increases nutrient and oxygen delivery, extends the anagen (active growth) phase of the hair cycle.
Evidence: Multiple large-scale clinical trials. 2% and 5% formulations approved by health authorities in multiple countries. Established to reduce shedding and regrow hair in androgenic hair loss in both men and women.
Limitations: Needs to be used continuously — stopping causes shedding to return. Takes 3 to 6 months to see visible results.
Redensyl
Redensyl is a patented active complex developed in France. See our full breakdown of Redensyl vs minoxidil. Unlike minoxidil, it works by targeting the outer root sheath stem cells (ORSCs) of hair follicles — the cells responsible for triggering new hair growth cycles.
How it works: Reactivates follicle stem cells and promotes the transition from the telogen (resting) phase to anagen (active growth). Also reduces inflammation around follicles.
Evidence: A clinical study found Redensyl reduced hair loss by 17% and increased total hair count by 9% over 84 days, outperforming minoxidil 3% in the same trial on some measures. Several independent studies have confirmed efficacy.
Limitations: Works best as a leave-in topical applied directly to the scalp. In rinse-off products (shampoos), benefit is reduced due to short contact time.
CtoMi’s PROSPER Follicle Booster Serum features Redensyl as a core active, designed for leave-in scalp application.
Finasteride (Oral, Prescription)
Finasteride is a prescription medication that inhibits the conversion of testosterone to DHT. Since DHT is the primary hormone responsible for androgenic hair loss (male pattern baldness), blocking its production at the source has significant effect.
Evidence: Extensively studied. Clinical trials show 80–90% of men stop further hair loss; around 65% experience some regrowth. One of the most effective interventions available for male androgenic hair loss.
Limitations: Prescription only. Associated with sexual side effects in a small percentage of users. Not appropriate for women of childbearing age. Requires ongoing use.
Ketoconazole Shampoo (1–2%)
Ketoconazole is an antifungal that also inhibits 5-alpha-reductase — the enzyme that converts testosterone to DHT — on the scalp. Studies have shown it reduces scalp DHT levels and can reduce shedding comparably to minoxidil 2% in some trials.
Evidence: Randomised controlled trials support efficacy for androgenic hair loss. Often recommended as an adjunct treatment.
Note: Requires consistent use (two to three times per week). Anti-dandruff shampoos containing 1% ketoconazole (like Nizoral) are widely available in NZ.
Platelet-Rich Plasma (PRP)
PRP involves drawing a patient’s blood, concentrating the platelets, and injecting them into the scalp. Growth factors in platelets stimulate follicle activity.
Evidence: Multiple studies show positive results for androgenic hair loss, particularly combined with minoxidil. Considered an evidence-based option by dermatologists.
Limitations: Requires clinic visits (not a home treatment). Cost can be significant over multiple sessions.
Products That Are Mostly Hype
Biotin Supplements (for most people)
Biotin deficiency does cause hair loss — but genuine biotin deficiency is rare in people who eat a balanced diet. For the vast majority of people taking biotin supplements, there’s no hair growth benefit because they weren’t deficient in the first place.
If you eat eggs, nuts, whole grains, or dairy, you’re almost certainly getting adequate biotin. Expensive biotin supplements are largely unnecessary unless a blood test confirms deficiency.
Collagen Supplements for Hair
Collagen peptides may benefit skin elasticity and joint health. But collagen ingested orally is broken down into amino acids during digestion — it doesn’t travel intact to your hair follicles. The marketing of collagen for hair growth is substantially ahead of the evidence.
Most “DHT Blocking” Shampoos Without Ketoconazole
Shampoos labelled as “DHT blocking” using herbal ingredients like saw palmetto, pumpkin seed, or rosemary oil have weak or mixed evidence compared to ketoconazole. Saw palmetto has some emerging data; pumpkin seed oil has one small trial. Neither comes close to ketoconazole or finasteride in evidence quality.
This doesn’t mean they’re worthless — but they’re nowhere near proven.
Laser Combs and LLLT Devices (Low-Quality End)
Low-level laser therapy has evidence at specific wavelengths and device quality levels. Medical-grade LLLT devices (FDA-cleared) have supporting data. Cheap “laser comb” products from general retailers typically don’t meet the specifications of the devices used in clinical trials and are unlikely to deliver meaningful results.
A Practical Framework for Building a Hair Growth Routine
Rather than buying one product and hoping for a miracle, effective hair loss management treats it like any other health condition — systemically and consistently.
Step 1: Address scalp health A healthy scalp is the foundation. This means regular cleaning with an appropriate shampoo (ketoconazole if DHT or dandruff is a factor, Redensyl-based like THRIVE if you want active support), managing scalp inflammation, and maintaining circulation. Read our guide to choosing the right hair growth shampoo in NZ.
Step 2: Apply a leave-in active treatment A serum applied to the scalp and left in provides far greater active ingredient delivery than any rinse-off product. Redensyl serum applied daily gives follicle stem cells consistent stimulation.
Step 3: Support follicle nutrition internally Hair follicles require specific micronutrients: iron, zinc, vitamin D, biotin (if genuinely deficient), and adequate protein. A targeted hair supplement addresses deficiencies that topical products cannot fix. CtoMi’s Hair & Follicle Nutrition formula supports this systemic layer.
Step 4: Address hormonal factors if relevant If androgenic hair loss is the primary concern, topical minoxidil or (for men) consulting a doctor about finasteride provides the hormonal dimension that topical products can’t.
Step 5: Be consistent for at least six months Most people give up too early. Hair cycle changes take time. Any effective routine needs to be maintained for a minimum of three to six months before evaluating whether it’s working.
FAQ
What’s the fastest-working hair growth product? Minoxidil consistently shows the fastest measurable results in clinical settings — typically visible improvement in 4 to 6 months. Redensyl in some trials has shown results within 3 months. No topical product works faster than the hair growth cycle allows.
Do hair growth supplements actually work? Supplements work when deficiency is the cause of hair loss. If you’re iron deficient, correcting it restores hair. If you’re not, supplementing won’t help. Comprehensive supplements addressing multiple follicle nutrition factors — like CtoMi’s Hair & Follicle Nutrition — are most useful as part of a complete routine.
Can women use the same hair growth products as men? Most topical treatments (minoxidil 2%, Redensyl, ketoconazole shampoo) are appropriate for women. Finasteride is not recommended for women of childbearing age. Always check product guidance and consult a healthcare professional if unsure.
How do I know if my hair loss is due to DHT or something else? Androgenic hair loss (pattern baldness) follows characteristic recession patterns — hairline in men, diffuse thinning at the crown in women. Sudden diffuse shedding is more often related to stress, illness, nutritional deficiency, or hormonal changes. A dermatologist or trichologist can provide an accurate diagnosis.
Is CtoMi’s hair range suitable for NZ conditions? Yes — CtoMi products are formulated and sold in New Zealand, designed for the NZ market. Browse the full range at ctomi.co.nz.
Stop Buying Hope, Start Buying Evidence
The hair growth products that work are known. The mechanisms are understood. The clinical trials exist. The gap between what works and what sells is almost entirely a marketing problem, not a science problem.
Invest in products with credible active ingredients at meaningful concentrations, use them correctly, and be patient. Hair health responds to consistent, evidence-based care — not expensive impulse buys.
Explore CtoMi’s hair growth range in NZ — PROSPER Follicle Booster Serum, THRIVE Hair Growth Shampoo, and Hair & Follicle Nutrition formulated to work together.
