We give a characterization of $L^{p}(\sigma)$ for uniformly rectifiable measures $\sigma$ using Tolsa’s $\alpha$-numbers, by showing, for $1<p<\infty$ and $f\in L^{p}(\sigma)$, that $$||f||_{L^{p}(\sigma)}\sim ||\left(\int_{0}^{\infty} \left(\alpha_{f\sigma}(x,r)+|f|_{x,r}\alpha_{\sigma}(x,r)\right)^2 \frac{dr}{r} \right)||^{\frac{1}{2}}_{L^{p}(\sigma)}.$$