Voted Best Spa — San Mateo Area, 2026
More than just a head spa
Most people care for their face but forget the skin where their hair grows. At Cosh, we’re changing that.
Our specialists are trained in scalp and hair health, not just technique. Whether you're navigating hair thinning, an unknown scalp concern, or just need a reset, Cosh is your space to unwind, learn, and heal - one strand at a time.
Backed by science
We don’t guess - we study. Every step of each treatment is rooted in intention and care and is backed by science, clinical research, and hands-on expertise.
We tailor everything to your scalp’s needs, taking our time to notice the small details that make a big difference.
Real People, Real Results
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Hair Loss
Before and 2 months after regular treatments.
This person was experiencing thinning and hair loss, most noticeable at their cowlick. After monthly Detox treatments, regular care at home, and daily use of Rootcoz serum, there is obvious, new hair growth with less scalp showing at the cow lick.
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Flakiness
Before and after Detox treatment.
Client complained about unmanageable flakiness. After cleaning their scalp with a personalized suite of products to balance the scalp’s microbiome, we sent them home with recommendations for a care routine meant for their scalp type.
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Oiliness & Buildup
Before and after Detox treatment.
This client complained about severe oiliness, and under the microscope, we confirmed severe buildup in pores which were causing oily flakes to get stuck in their hair. We treated with an oil control product and made recommendations to adjust their cleansing technique and frequency.
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Wrong Shampoo
Before and after Rejuvenate treatment.
Client came to us complaining about hair loss. We found that they had an oily scalp and weren’t shampooing at the right frequency or with the right product for their scalp type. We cleaned their scalp, provided recommendations for better care, and treated with red light therapy to help promote activity in hair follicles.
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Flakiness on Dry Scalp
Before and after Detox treatment.
Client came in with an itchy, flaky scalp. We found that their shampoo frequency wasn’t right for their scalp type, causing oil accumulation to flake off and stick in their hair. We corrected the flakiness issue with an adjustment to their shampoo frequency and resolved the itch with the right product for their concerns.
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*Only for returning clients
Just the wash. A quick look at your scalp helps us choose the right products, then we double shampoo, condition, and rough dry. No extras—just clean, simple, and straight to the point.
Ideal for anyone who just wants a quick, no-frills shampoo with professional-grade, plant-based products.
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Your scalp’s reset button. This treatment includes a thorough scalp analysis, invigorating head massage, double shampoo, nourishing hair mask with steam, conditioning, and a rough dry—for a clean slate and clear mind.
Ideal for our routine maintenance clients, or anyone looking for a good cleanse with some added massage to unwind with a foundational, feel-good experience.
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A deeper clean for stressed scalps. Includes everything in our Refresh treatment, plus scalp exfoliation, a tension-relieving gua sha ritual, and extended steam to deeply nourish and moisturize.
Ideal for head spa first-timers who aren’t sure about what direction to go, those with product buildup, scalp congestion, or high stress levels who want a deeper clean and more targeted relief.
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Where relaxation meets regeneration. Building on Detox, this treatment adds extended head massage time and red light therapy to boost circulation and hair follicle activity, calm inflammation, and promote and support healthy hair growth.
Ideal for clients seeking deeper relaxation and scalp regeneration—especially helpful for those with hair thinning concerns or chronic tension.
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The best of both worlds. This treatment pairs our signature hands-on ritual (everything in Detox, minus scalp exfoliation) with Hydrafacial’s Keravive—a high-tech scalp treatment that uses a proprietary blend of peptides and growth factors to deeply cleanse, nourish, and stimulate the scalp, creating the ideal environment for fuller, healthier hair.
Ideal for clients serious about hair growth and scalp health who want the combined power of holistic hands-on care and advanced, research-backed technology.
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A return to roots—literally. This treatment includes everything in Rejuvenate, but swaps bottled products for handcrafted scalp oil, exfoliant, and hair mask made from whole, natural ingredients. Plus, enjoy the soothing benefits of Luk Pra Kob, a warm Thai herbal compress that melts away stress and tension, soothes the senses, and calms the scalp..
Ideal for pregnant or nursing women, or anyone looking to avoid synthetic ingredients and embrace an all-natural, handmade approach to scalp wellness.
Scalp Treatments
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Because sometimes, ten more minutes is exactly what your nervous system needs.
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A quiet escape. Enjoy your treatment in a fully private room for extra peace and presence.
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Boosts blood flow, invigorates the hair follicles, and calms inflammation to promote growth and support a healthier scalp and stronger strands.
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A powerful, plant-based serum designed for hereditary hair thinning. Supports fuller growth over time.
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For sudden hair loss due to stress, seasonal changes, medication, hormonal fluctuations, and fatigue. This targeted treatment helps rebalance, re-anchor, and nourish the scalp.
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A soothing facial tailored to your skin type and concerns, whether it’s locking in moisture, attacking signs of aging, or sucking away excess oil. Glowy finish included.
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A traditional Thai herbal compress used to massage your head and neck that melts away tension while promoting scalp circulation and relaxation. Luk Pra Kob has analgesic (pain-killing) and aromatherapy properties.
Service Enhancements
Hydrafacial Treatments
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A deep reset for your skin. Includes a manual double cleanse, exfoliation, painless extractions, targeted serums to hydrate, clarify, and brighten, and red light therapy —powered by Hydrafacial’s advanced technology.
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Our most comprehensive facial experience. Includes everything in Purify, plus lymphatic drainage, dermaplaning, and a targeted Eye & Lip Perk for that extra-fresh finish—starting, as always, with our signature double cleanse.
We study the scalp. We care for the person.
"I walked out with way more hair/scalp knowledge and way less stress."
— M S., Peninsula, CA
what our clients are saying
"Every touch and step felt intentional, and by the end, my scalp was revitalized and my hair had never felt softer. It's not just a treatment, it's an experience."
— Karen F., Belmont, CA
"If you're looking for a unique form of self-care that goes beyond the surface, I cannot recommend Cosh Head Spa enough. I left feeling not only pampered, but genuinely renewed."
— Traci D., San Bruno, CA
"When you enter you are immediately transported to a calm place. I've never had a head spa before but after this experience I can't imagine going anywhere else."
— Katy C., San Francisco, CA
Designed With Intention. Down to the Last Drop.
Every inch of Cosh was created with care—to soothe your senses, elevate your experience, and deliver results that go beyond skin-deep.
Filtered & Softened Water
Our advanced filtration system removes harsh minerals and chemicals, leaving water that’s gentler on your scalp and hair. With a balanced pH, it helps seal the hair cuticle and boosts the effectiveness of every treatment.
Custom Chairs & Sink Bowls
Our fully-reclining chairs and ergonomic sink bowls are custom-built for total comfort. No awkward transitions, no shifting stations—just uninterrupted relaxation from start to finish.
Mood Lighting
Our dimmable, strategically-placed lighting creates a calming glow that eases eye strain and quiets the mind. Whether you're here for a quick refresh or a longer ritual, the light sets the tone for true tranquility.
Signature Scent
Subtle botanical notes float through the space, grounding you the moment you arrive. Our signature scent is designed to calm the nervous system and turn your visit into a sensory escape.
Curated Soundscape
Soothing, atmospheric sounds are carefully chosen to slow your breathing and settle your thoughts. Every playlist is designed to enhance stillness and support deep relaxation.
Because healing the scalp and calming the soul work best when the space around you is designed with both in mind.
“Beautiful hair grows from a healthy scalp like a plant in fertile soil.”
—Rene Furterer, Founder of Rene Furterer Paris
Plan Your Visit!
Get to know your specialist, find out about parking and things to do in the area, or check out our frequently asked questions.
Get to know our team before you come in.
Parking tips and things to do in the area
