29 year old female with relatively mild neck laxity - what are my most effective non-surgical options? (Photo)

Thank you for you question. I think Kybella is a great option. Laxity comes from loss of skin turgor. Kybella melts fat which can help improve the lax skin. 

From your description Morpheus8 sounds like the right treatment for you. This is a noninvasive approach that combines RF technology with microneedling to improve overall skin tone and texture. Typically three treatment sessions are recommended for optimal results. We also recommend using medical grade skin care products like Transform MD and wearing sunscreen every day.

Our Hidef approach to non surgical neck lifting addresses underlying
muscle hypertrophy, neck laxity, and fascial tightness. We use a
combination of Venus Legacy RF, NanoRF, and Ultherapy to exact a
tightening of the neck + Botox for muscle and masseter hypertrophy.
Retinoid creams are a must and we follow a comprehensive cream program
for topical creams. 
Finally, fractional laser offers the benefits
of microablation to improve skin quality and texture. We use this in
addition to light therapy and PRP.

Best, 
Dr. Karamanoukian
Realself100 Surgeon