Best Shampoo pH for Long-Lasting Keratin Treatments & Nanoplasty

A fresh keratin blow-out or nanoplasty can stay glossy for up to three or more months—if you baby it with the right after-care. The single most important number on the bottle is pH. Here’s why an acidic, skin-like pH keeps your treatment locked in and how to choose the perfect cleanser.

Why pH matters
• Hair fibre and scalp sit at pH 4.5–5.5.
• Keratin and nanoplasty treatments create new cross-links that are stable in mild acid but swell and break in alkaline conditions.
• Many classic shampoos measure pH 7.0–9.0; every wash in that range opens the cuticle, leaches out smoothing agents and shortens treatment life.

Ideal pH window
• Target shampoo pH: 4.0–5.5.
• Sweet spot: 4.5–5.0—low enough to seal the cuticle, high enough to avoid scalp sting.

Key shopping cues
• Look for “pH-balanced” plus an actual number on the label. If none is listed, litmus-test a sample; opaque marketing terms are unreliable.
• Sulfate-free surfactants (cocamidopropyl betaine, sodium cocoyl isethionate) cleanse without stripping the hydrophobic silicone layer deposited during the service.
• Avoid sodium chloride high on the ingredient list; salt swells the shaft and flushes out treatment polymers.
• Opt for added acids: lactic acid, citric acid or gluconolactone help hold the formula in the target range.

Care routine tips
• Wash no more than 2–3 times per week; in-between, use a low-pH dry shampoo.
• Rinse with cool water to keep the cuticle flat.
• Finish with a matching acidic conditioner or leave-in spray (pH 3.5–4.5) for extra cuticle sealing.
• Heat-style under 180 °C/350 °F; higher temperatures oxidise cross-links.

Bottom line
An acidic, sulfate-free shampoo at pH 4.5–5.0 is the simplest insurance policy for keeping keratin treatments and nanoplasty glass-smooth far beyond the usual fade-out date