Natural, non-colored, chemically untreated hair only, not for hair that's been dyed, bleached, or chemically straightened or permed (that's System 3 or higher). Progressed (more advanced/noticeable) thinning specifically, not early/light thinning, which is System 1's audience. People already using, or willing to add, the matching System 2 shampoo and conditioner. Consumer, at-home use; no professional application required, though it's commonly recommended by stylists.

The reason this exists as a separate leave-in step, rather than just folding more actives into the shampoo or conditioner, is contact time: a shampoo is rinsed out within a minute or two and a conditioner shortly after, so anything meant to actively work on the scalp needs a product that isn't washed away to actually stay in contact with skin.

Use as the third and final step of the Nioxin System 2 routine, after System 2 Cleanser Shampoo and System 2 Scalp Therapy Conditioner, not on its own.

• Towel-dry hair after shampooing and conditioning
• Apply the treatment directly to the scalp and areas of concern
• Massage gently to distribute evenly
• Do not rinse out
• Style hair as usual
• For visible results, use the full System 2 routine at least three times per week for about 30 days

• No-rinse format means active ingredients stay on the scalp rather than being washed off seconds after application
• Specifically formulated for the progressed-thinning stage, rather than a generic thickening product used at any stage
• Includes UV-protecting ingredients, which most leave-in scalp treatments skip
• Only works as part of the full three-step System 2 kit - using it alone, or with a mismatched system's shampoo/conditioner, isn't how Nioxin designed it to perform
• Results are cosmetic thickening/fuller appearance, not a treatment for the underlying causes of hair loss
• Requires consistent use, three or more times weekly for about a month, before results are noticeable